INVERT EMULSION DRILLING FLUID Russian patent published in 2022 - IPC C09K8/36 

FIELD: invert-emulsion drilling fluids.

SUBSTANCE: invention relates to invert-emulsion drilling fluids for drilling overproductive intervals and penetrating productive formations during the construction and reconstruction of wells. The invert emulsion drilling fluid includes a hydrocarbon liquid, an emulsifier-stabilizer, a saline water phase and a solid phase additive. At the same time, as an emulsifier-stabilizer, the solution contains a mixture of an amphiphilic oil-soluble acrylic copolymer with modified esters of C16-C18 fatty carboxylic acids dissolved in polyhydric alcohol, and contains sulfonated bitumen as a solid-phase additive. The components are included in the solution in the following ratio, wt.%: hydrocarbon liquid - 33-60; specified emulsifier-stabilizer - 1.8-4.0; sulfonated bitumen - 0.2-1.0; mineralized aqueous phase - the rest, while the mass ratio of the specified acrylic copolymer with the specified esters of fatty carboxylic acids, dissolved in polyhydric alcohol, is 1: (3-8), respectively.

EFFECT: invention provides an increase in the stability of the parameters of the drilling fluid when exposed to elevated temperatures with a simultaneous increase in its remote, inhibitory and bridging abilities.

5 cl, 2 tbl, 2 ex